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United States Patent |
5,503,764
|
Murch
,   et al.
|
April 2, 1996
|
Produce cleaning article containing potassium oleate
Abstract
Basic cleaning compositions using toxicologically-acceptable ingredients
for cleaning fruits and vegetables are provided. Clear liquid formulations
comprising oleate, alcohol ethoxylates and buffers are sprayed onto
apples, lettuce and the like to remove soil and unwanted deposits.
Inventors:
|
Murch; Bruce P. (Cincinnati, OH);
Roselle; Brian J. (Fairfield, OH);
Jones; Kyle D. (West Chester, OH)
|
Assignee:
|
The Procter & Gamble Company (Cincinnati, OH)
|
Appl. No.:
|
270860 |
Filed:
|
July 5, 1994 |
Current U.S. Class: |
510/111; 510/406; 510/421; 510/437 |
Intern'l Class: |
C11D 017/00 |
Field of Search: |
252/90,108,173,174.21,DIG. 14,DIG. 1,156
134/25.1,25.3,42
|
References Cited
U.S. Patent Documents
4002579 | Jan., 1977 | Mizutani et al. | 252/544.
|
4082223 | Apr., 1978 | Nozawa | 239/333.
|
4140649 | Feb., 1979 | Bossert et al. | 252/105.
|
4177294 | Dec., 1979 | Lehmann et al. | 426/271.
|
4244975 | Jan., 1981 | Herbst et al. | 426/271.
|
4259216 | Mar., 1981 | Miyajima et al. | 252/545.
|
4287102 | Sep., 1981 | Miyajima et al. | 252/547.
|
4414128 | Nov., 1983 | Goffinet | 252/111.
|
4808330 | Feb., 1989 | Chung | 252/170.
|
4857345 | Aug., 1989 | Sardo | 426/310.
|
5075026 | Dec., 1991 | Loth et al. | 252/122.
|
5100055 | Mar., 1992 | Rokitenetz et al. | 239/11.
|
5280042 | Jan., 1994 | Lopes | 514/557.
|
5306444 | Apr., 1994 | Kitamura et al. | 252/546.
|
5320772 | Jun., 1994 | Tricca | 252/160.
|
Foreign Patent Documents |
4023418A1 | Feb., 1992 | DE | .
|
05262617A | Mar., 1992 | JP.
| |
Other References
Code of Federal Regulations, Food and Drugs, Part 21 (Apr. 1992)
.sctn.173.315, "Chemicals used in washing or to assist in the lye peeling
of fruits and vegetables".
|
Primary Examiner: Einsmann; Margaret
Assistant Examiner: Douyon; Lorna M.
Attorney, Agent or Firm: Aylor; Robert B.
Claims
What is claimed is:
1. A produce cleaning article comprising a spray container containing a
cleaning solution which consists essentially of:
(a) from about 0.1% to about 5% by weight of potassium oleate;
(b) optionally, from about 0.1% to about 4% by weight of a nonionic
surfactant;
(c) optionally, from about 0.2% to about 4% by weight of organic
polycarboxylate detergency builder;
(d) optionally, a toxicologically-acceptable basic buffer; and
(e) the balance being water or water-ethanol fluid, which has a pH of at
least about 9.5 to about 12.5, wherein said spray container comprises
manually-activated, trigger-type, spray means.
2. The article of claim 1 wherein said potassium oleate and said nonionic
surfactant are generally regarded as safe.
3. The article of claim 2 wherein said solution contains from about 0.75%
to about 5% by weight of said potassium oleate.
4. The article of claim 3 wherein said solution contains from about 1% to
about 5% by weight of said potassium oleate.
5. The article of claim 1 wherein said solution has a pH of from about 9.5
to about 12.3.
Description
TECHNICAL FIELD
The present invention relates to methods for removing dirt and other
unwanted residues from produce, e.g., fruits and vegetables, which is
intended for ingestion by humans or lower animals and to detersive
compositions, especially in liquid form, which are especially suitable for
practicing said methods.
BACKGROUND OF THE INVENTION
It is well-known and appreciated by consumers that fruits and vegetables
should be thoroughly washed prior to ingestion in order to remove soils
and other unwanted residues which may be undesirably clinging to the
surfaces thereof. In addition, some consumers wish to remove the
artificial "waxy" coatings which may be applied to some fruits to retard
moisture loss for increased storage life and to enhance their appearance.
It has been estimated that 95% of consumers recognize the need for
thorough washing but, ordinarily, only use tap water for this purpose. On
the order of 5% of those consumers who do wash their vegetables use a
household cleaner, typically a liquid dishwashing product, to help ensure
cleanliness. However, dishwashing products are not specifically intended
for such use, inasmuch as they are usually designed to provide high,
persistent suds which makes them inconvenient to remove from the fruits or
vegetables which have been washed therewith. It will also be appreciated
that the formulation of truly effective compositions, especially those
which can be used safely by individual consumers, for washing fruits and
vegetables presents a unique problem to the formulator, inasmuch as many
an-disclosed cleaning ingredients would, presumably, not be desirable for
use in direct contact with foods where they might not be fully removed.
Moreover, it would be especially desirable to provide effective,
toxicologically-acceptable cleaning compositions for fruits and vegetables
in the form of substantially low-sudsing liquid solutions which are clear
or which have only minimal haziness. Liquid solutions are convenient for
the user, since they can be applied directly to soiled fruits and
vegetables, followed by rinsing in tap water. The clarity of the liquids
connotes cleanliness to the user and is thus highly desirable. Low sudsing
is an important attribute so that removal of the solution by rinsing is
achieved quickly and easily. It would also be of advantage if such
compositions could be provided in the form of concentrates, which could be
diluted by the consumer before use and/or applied to the fruits and
vegetables as a direct spray-on.
Unfortunately, many toxicologically-acceptable cleaning ingredients do not
meet the aforesaid requirements for clear, low-sudsing, dilutable liquid
products. Many detersive surfactants form cloudy or even opaque
suspensions in water. Of course, many surfactants are specifically
designed to be high sudsing. Still others form relatively intractable
phases in their concentrated form.
It has now been discovered that certain nonionic surfactants, properly
formulated with oleic acid or water-soluble oleate or laurate salts and
other ingredients can provide liquid compositions having the desired
properties described above. It has been discovered that preferred
compositions can be formulated in the acid pH range and have a desirable
clean, "non-soapy" feel to the user's hands. Alternatively, certain
compositions can be formulated in the basic pH range. Even when such basic
compositions do have a soapy feel, they are preferred over the acidic
compositions herein for removing artificial waxy coatings, especially from
fruit such as apples. However, the invention also comprises basic
compositions having less soapy feel.
BACKGROUND ART
The use and selection of cleaning ingredients for the purpose of washing
fruits and vegetables is described by the United States Code of Federal
Regulations, Title 21, Section 173.315: "Ingredients for use in washing or
lye peeling of fruits and vegetables". These regulations restrict the
ingredients that may be used for direct contact with food to those
described as "generally regarded as safe" (GRAS), and a few other selected
ingredients. These sections also provide certain limitations on the amount
of material that can be used in a given context.
Among these ingredients, the experienced formulator will find only a few
ingredients which can provide effective cleaning of hydrophobic residues,
such as waxes, oils, or man-made chemical residues such as pesticides. It
is recognized that these types of residues are removed most readily by
surface active ingredients in water, or by organic solvents largely in the
absence of water. Other types of soils, especially particulate insoluble
soils that do not readily disperse in water, are effectively removed by
surface active materials in water, especially when aided by complex
anionic salts, such as citrates (polycarboxylates), or polyphosphate
salts.
Within this limited group of ingredients the range of effective cleaning
compositions well suited to the task of cleaning fruits and vegetables,
especially as practiced by individual consumers, have not been previously
described. It is desirable to formulate liquid compositions which are
amenable to either direct application to produce, preferably by spray
application, or could be provided in suitable concentrated form to allow
convenient dilution in a bowl or sink of water for washing of produce by
immersion. Further, it is desirable the compositions are low sudsing, and
easily rinsed, without leaving residue. Preferred compositions should be
mild to the hands, especially for direct application.
Food Chemical News, Inc., 1991, p. 334.1, reports that PEG 200-9500 has
been cleared under .sctn.178.3750 as a component in articles for use in
contact with food (Fed. Register, Oct. 15, 1968). Nonetheless, for washing
produce, polyethylene glycol should be affirmed as GRAS.
SUMMARY OF THE INVENTION
The present invention encompasses methods for cleaning produce, especially
fruits and vegetables, (and compositions, as disclosed hereinafter, for
practicing said methods) at either an acidic pH, or basic pH. The present
invention comprises several aspects including:
I. A method for cleaning produce comprising contacting the surfaces of said
produce by direct application of an aqueous cleaning solution typically
comprising:
(a) from about 0.01% to about 15% of C.sub.8 -C.sub.18 fatty acid, and
preferably less than about one eighth of the amount of nonionic surfactant
in an acidic product;
(b) optionally, except that it is required when the pH is less than about
5.5, from about 0.1% to about 4% by weight of nonionic surfactant,
especially ethoxylated/propoxylated adducts of aliphatic C.sub.12-18
alcohols;
(c) optionally, from about 0.1% to about 4% by weight of organic
polycarboxylic acid, preferably citric acid;
(d) optionally, up to about 0.2% by weight of an acid-stable anionic
surfactant such as the alkali or alkaline earth salts of dodecylbenzene
sulfonate;
(e) optionally, a toxicologically-acceptable acidic buffer, other than said
polycarboxylic acid and/or said fatty acid, sufficient to maintain the
desired pH;
(f) optionally, a toxicologically-acceptable basic buffer such as potassium
and/or sodium salts of carbonate and/or bicarbonate;
(g) optionally, a toxicologically-acceptable preservative; and
(h) the balance comprising an aqueous carrier selected from water and,
optionally, low molecular weight, toxicologically-acceptable organic
solvent such as ethanol, glycerol, etc.;
wherein said aqueous solution has a pH either in the range of from about
2.5 to about 5.5, preferably about 4, or in the range of 9.5 or greater,
and preferably employs potassium carbonate as buffer (f) to provide a pH
of about 11, said composition preferably being essentially free of any
material that is not toxicologically acceptable.
I(A) The inventions disclosed herein can preferably encompass a method for
cleaning produce, e.g., fruits and vegetables, at an acidic pH comprising
contacting the surfaces of said produce by direct application with an
aqueous cleaning solution comprising:
(a) from about 0.1% to about 4% by weight of nonionic surfactant,
preferably non-nitrogen containing nonionic detergent surfactant,
especially ethoxylated/propoxylated adducts of aliphatic C.sub.12-18
alcohols;
(b) from about 0.01% to about 0.4% by weight of oleic acid, the ratio of
nonionic detergent surfactant to oleic acid being more than about 8:1;
(c) from about 0.1% to about 1.5% by weight of organic, preferably
naturally derived, organic polycarboxylic acid, e.g., citric acid;
(d) optionally, a toxicologically-acceptable acidic buffer, especially
potassium hydrogen citrate, sufficient to maintain the desired pH;
(e) optionally, up to about 0.2% by weight of an acid-stable anionic
surfactant such as the alkali or alkaline earth salts of dodecylbenzene
sulfonate;
(f) optionally, a toxicologically-acceptable preservative; and
(g) the balance comprising an aqueous carrier;
wherein said aqueous solution has a pH in the range of from about 2.5 to
about 5.5, preferably about 4.
I(B) The inventions disclosed herein can also preferably encompass a method
for cleaning fruits and vegetables at a basic pH, comprising contacting
the surfaces of said fruits and vegetables with an aqueous cleaning
solution comprising:
(a) optionally, from about 0.1% to about 4% by weight of nonionic
surfactant, especially ethoxylated/propoxylated adducts of aliphatic
C.sub.12-18 alcohols;
(b) from about 0.1% to about 15% by weight of a member selected from the
group consisting of sodium or potassium oleate (preferred) or from about
0.5% to 10% by weight of sodium or potassium laurate;
(c) optionally, but preferably, from about 0.2% to about 4% by weight of
potassium and/or sodium polycarboxylate, having detergent building
capability and preferably being derived from natural sources, such as
potassium and/or sodium citrate, as a dispersant for particulate soils;
(d) optionally, a toxicologically-acceptable basic buffer such as potassium
carbonate; and
(e) the balance comprising an aqueous carrier selected form water and
water-ethanol;
wherein said aqueous cleaning solution has a pH of 9.5 or greater, and
preferably employs carbonate salt, or salts, as buffer (d) to provide a pH
of about 11 to about 12.5.
I(C) The inventions herein can also encompass a more specific method for
cleaning fruits and vegetables at a basic pH, preferably more than about
9.5, comprising contacting the surfaces of said fruits and vegetables with
an aqueous cleaning solution comprising potassium oleate, preferably at a
level of more than about 0.5%. Potassium oleate is mild, rinses well, has
minimal odor, is effective in removing unwanted materials, especially wax,
from apples, does not oversuds, and is very safe, even when the
composition is misused and the vegetable, or fruit, etc., is not
completely rinsed. Therefore, it is a uniquely preferred surfactant for
use in cleaning food materials like vegetables and fruits. The potassium
cation is much more useful than the sodium cation since the potassium
oleate is quite soluble whereas the sodium oleate tends to form a less
soluble soap, especially at low temperatures.
I(D) Another preferred, concentrated, alkaline method for cleaning produce
comprises contacting the surfaces of produce with a cleaning solution
containing from about 0.5% to about 15%, preferably from about 0.75% to
about 8%, more preferably from about 1% to about 5%, detergent surfactant,
preferably one that is GRAS, and more preferably said oleate surfactant
said cleaning solution having a pH of from about 8 to about 12.5,
preferably from about 9.5 to about 12.3, especially when the detergent
surfactant is a soap such as the said oleate, more preferably from about
11 to about 12. Such compositions when used in an effective amount to
clean apples coated with wax, will provide effective removal of the wax.
Removal of wax from apples is one of the most difficult cleaning tasks and
therefore is indicative of overall superior performance.
I(E) Yet another preferred variation in the above methods for cleaning
produce involves placing said cleaning solutions in a spray container to
provide a spray of said solution to distribute the said solution, or
solutions, over the surfaces of the produce while utilizing only a minimum
amount of the cleaning solution and minimizing the exposure of the
remaining solution to the atmosphere, where the solution is more likely to
be contaminated and/or exposed to oxygen, both of which tend to cause
undesirable changes in the solutions from aesthetic and/or performance
considerations. In such spray processes, there is only need for a
relatively small amount of material in the package, and for individual
consumer use, this is desirable, since some consumers will not be able to
manipulate large weights. For consumer usage, typically, the container
will contain no more than about two gallons (about four liters),
especially when the container is a spray container, even one that has a
tube that permits the spray device to be manipulated while the bulk
container remains in place. Preferably such spray containers contain about
one liter, or less, of cleaning solution.
II. The invention also encompasses acidic and basic cleaning compositions
in both concentrated and dilute forms, especially adapted for practicing
said methods. (In the following disclosure, the lower amounts of the
specified ingredients denote the dilute forms of the compositions herein
and the higher amounts denote the concentrated forms which are typically
diluted by a factor of from about 2 to about 3.) Such compositions include
the following.
II.(A) A composition for cleaning fruits and vegetables at an acidic pH,
comprising:
(a) from about 0.1% to about 7.5%, preferably from about 0.3% to about
4.5%, by weight of nonionic surfactant, as described above;
(b) from about 0.01% to about 0.75%, preferably from about 0.1% to about
0.5%, by weight of oleic acid, the ratio of oleic acid to nonionic
detergent
surfactant being less than about 1:8;
(c) from about 0.1% to about 7.5%, preferably from about 0.3% to about
4.5%, by weight of organic polycarboxylic acid, preferably citric acid;
(d) optionally, a toxicologically-acceptable acidic buffer;
(e) optionally, a toxicologically-acceptable preservative; and
(f) the balance comprising an aqueous carrier;
wherein said composition has a pH in the range of from about 2.5 to about
5.5.
Preferably, the acidic compositions herein contain from about 0.5% to about
3.0% by weight of potassium citrate as the acidic buffer (d) and have a pH
of about 4. Optionally, such compositions can contain up to about 1%,
preferably about 0.2%, by weight of an acid-stable anionic surfactant, as
described above.
II.(B) A composition for cleaning fruits and vegetables at a basic pH,
comprising:
(a) optionally, from about 0.1% to about 4%, preferably about 0.3% to about
1.0%, by weight of nonionic surfactant as described above;
(b) from about 0.1% to about 15%, preferably from about 1% to about 5%, by
weight of a member selected from the group consisting of sodium or
potassium oleate (preferred), sodium or potassium laurate, or mixtures
thereof;
(c) from about 0.2% to about 4% by weight of polycarboxylic acid salt,
especially potassium hydrogen citrate;
(d) optionally, a toxicologically-acceptable basic buffer; and
(e) the balance comprising an aqueous carrier selected from water and
water-ethanol;
wherein said composition has a pH of 9.5 or greater.
Preferably, the basic compositions herein contain from about 0.5% to about
1.5% by weight of potassium and/or sodium carbonate buffer and have a pH
of about 11.5.
II.(C) Preferred compositions for use herein in a concentrated alkaline
method contain from about 0.1% to about 15%, preferably from about 0.5% to
about 8%, more preferably from about 1% to about 5%, detergent surfactant,
preferably one that is GRAS, and have a pH of from about 8 to about 12.5,
preferably from about 9 to about 12.3, more preferably from about 11 to
about 12. Such compositions when used in an effective amount to clean
apples coated with wax, will provide effective removal of the wax. Removal
of wax from apples is one of the most difficult cleaning tasks and
therefore is indicative of overall superior performance.
II.(D) The present invention also encompasses detersive compositions with
an improved tactile impression which are especially adapted for cleaning
fruits and vegetables, comprising:
(a) at least about 0.1%, preferably from about 0.5% to about 8%, most
preferably from about 1% to about 5%, by weight, of a C.sub.12 -C.sub.18
fatty acid or salt thereof;
(b) at least about 0.05%, preferably from about 0.1% to about 10%, most
preferably from about 0.25% to about 3.0%, by weight, of a water-soluble
polyethylene glycol having a molecular weight of about 200, or higher;
(c) a water or water-ethanol fluid carrier, said composition having a basic
pH. The balance of the composition can comprise various optional adjunct
materials, pH-adjusting agents, perfumes or essences, preservatives and
the like.
In a preferred mode, component (b) has a molecular weight in the range from
about 400 to about 9500.
Typical compositions herein are wherein component (a) is potassium oleate,
and wherein the weight ratio of(a):(b) is in the range from about 1:2 to
about 15:1.
The compositions having improved tactile impression are typically
formulated in the basic pH range, preferably from about pH 9.5 to about pH
12.3. Preferred compositions have a viscosity at room temperature of less
than about 100 centipoise, preferably less than about 50 centipoise for
sprayable compositions.
II.(E) Preferred compositions for use herein contain only materials that
are GRAS to protect against possible misuse by the consumer.
Traditionally, most suggestions for cleaning of fruits and/or vegetables
have contemplated a commercial scale where there is typically more control
over the conditions, especially the amount and thoroughness of rinsing.
The present invention, especially the methods involving use of hand held
trigger activated spray means are primarily/solely suitable for use by
individual consumers so that it is essential that extra safety be built
into the product. Failure to rinse thoroughly after cleaning is less of a
concern if all of the ingredients are GRAS. This is especially important
when concentrated basic compositions suitable for removal of wax from
apples are used. The larger amounts of materials needed for removal of wax
create an heretofore unknown level of risk for the individual consumers,
many of whom are not likely to read, or follow, instructions which would
permit safe use of non-GRAS materials.
The ingredients in the above compositions are preferably selected and used
in proportions which provide substantially clear compositions.
Substantially clear includes only minimal haziness, and preferably the
compositions are completely clear. The ingredients are also selected to
have minimal odor, both initially and after storage. The lack of odor is
especially important in compositions for use on food. The compositions
preferably have a viscosity that is more than about 10 centipoise,
preferably more than about 50 centipoise when at rest, but thin under
shear to permit easy dispensing, especially from spray containers.
Below pH about 9.7, the compositions can exhibit some objectionable fatty
acid odor. Even at the optimal pH's above 11, some odor can persist. In
order to mask this odor, the compositions can contain a perfume or essence
ingredient. Especially preferred for this use are terpenes derived from
citrus fruit, e.g., oranges, lemons, limes, grapefruits, tangerines,
tangelos, etc.
All documents cited are incorporated herein by reference.
DETAILED DESCRIPTION OF THE INVENTION
The following toxicologically-acceptable ingredients are used in the
preparation of the preferred compositions herein. By
"toxicologically-acceptable" is meant that any residues from the
ingredients of the compositions which may remain on the fruits or
vegetables cleansed therewith are safe for ingestion by humans and lower
animals.
Nonionic Surfactant--The nonionic surfactant is preferably selected from
materials known well-known in the art, such as alkylene oxide (ethylene
oxide or propylene oxide) adducts of C.sub.10-18 aliphatic alcohols or
acids, C.sub.10-18 aliphatic alcohol adducts of glucose (alkyl
polyglucosides). The specific nonionic surfactant selected ideally has a
hydrophilic-lipophilic balance (HLB) greater than about 10, and a cloud
point above about 35.degree. C. in the composition. The United States Code
of Federal Regulations (CFR) specifically describes an ethylene
oxide/propylene oxide adduct of C12-18 aliphatic alcohol of molecular
weight of about 800. Such a material is available as PLURAFAC RA-20
(BASF).
It is to be appreciated that in the acidic compositions herein, the
alkoxylated alcohol functions substantially as a cleansing agent, whereas
in the basic compositions the alkoxylated alcohol functions mainly as a
dispersant for any soap curd which may form during the cleansing
operation. Further, it is recognized that the selection of non-nitrogen
containing nonionics can minimize the possibility of microbial growth in
the dilute surfactant compositions.
Fatty Acid and/or Salts Thereof--The acidic compositions herein are
formulated using an unsaturated fatty acid; oleic acid is preferred and
convenient for this use. However, the particular oleic acid that is
selected should preferably be low in polyunsaturates, e.g., contain less
than about 10%, preferably less than about 7%, more preferably less than
about 5% and will typically have an Iodine Value (IV) of from about 70 to
about 100, preferably from about 83 to about 95, more preferably from
about 85 to about 90. Polyunsaturated fatty acids are not preferred
herein, due to odor problems. However, this is primarily from aesthetic
considerations since such acids are effective in cleaning. The amount of
polyunsaturated fatty acids should be less than about 8%, preferably 0%.
The amount of polyunsaturated fatty acids with more than about two double
bonds should be less than about 1%, preferably 0%. Saturated fatty acids
are unacceptable as they have limited solubility for longer chainlength
materials (.gtoreq.C.sub.12), or have unacceptable odor
(.ltoreq.C.sub.14). For example, stearic and/or tallow fatty acids soaps,
even potassium soaps, do not have enough solubility at room temperature,
where most produce cleaning is done by individual consumers, to formulate
even compositions containing the minimum of about 0.1% soap required for
acceptable cleaning. Other specific solubilizing surfactants in higher
proportions would be required to solubilize these saturated fatty acids.
Pamolyn 100 FGK oleic acid is a good example of a suitable commercial
fatty acid.
For the acidic compositions, other low HLB (<6) nonionics can be
substituted, such as monoglycerides, but these are less preferred than
oleic acid. The purpose of these materials is to provide acceptable
cleaning with low sudsing to the compositions. Preferably, in the acidic
compositions the oleic acid is used in an amount that is less than about
1:8 (about 12%) by weight of the nonionic surfactant. For the basic
compositions, sodium oleate or sodium laurate can be employed, but only
sodium oleate is described as GRAS on the CFR. The fatty acid (or salt
thereof) functions both to provide a cleansing action and to dampen
sudsing. In the acidic formulation, the pH of very dilute mixtures is kept
below 7.0 by citric acid to prevent formation of cloudiness.
Polyethlene Glycol--The water-soluble polyethylene glycol polymer (PEG)
employed herein is the known article of commerce and is available under a
variety of trade names, of which CARBOWAX (Union Carbide Corporation) is
exemplary. PEG's in the average molecular weight range of from about 200
to about 20,000 can be used herein, and PEG as CARBOWAX in the average
molecular weight range of at least about 400, typically 400 to about 9500,
is convenient and preferred. As disclosed above, the compositions herein
will comprise at least about 0.05%, by weight, of the PEG and will
typically comprise from about 0.1% to about 10%, by weight, of PEG. The
amounts used can vary with the molecular weight of the PEG, the amount of
oleate or other fatty acid used in the composition, the desired viscosity
of the composition, and like factors within the discretion of the
formulator. The following Table 1 illustrates the variation in viscosity
which can be effected using various levels of PEG and varying PEG
molecular weights in a liquid composition (Control) comprising 3%
potassium oleate. Table 1 also illustrates the effect of sodium benzoate
(Bz) on viscosity.
TABLE 1
______________________________________
Viscosity Viscosity
(cP* as made)
(cP* as made)
Composition 72.degree. F. (22.degree. C.)
43.degree. F. (6.degree. C.)
______________________________________
Control (no PEG) 7 110
Control + 0.674% Bz
23 1000
Control + 0.118% Bz
7 159
Control + 0.1% PEG 400
5 36
Control + 0.5% PEG 400
2 17
Control + 0.1% PEG 8000
5 23
Control + 0.5% PEG 8000
8 4
______________________________________
*Viscosity in centipoise as measured using Brookfield LVTD #2 spindle, 60
rpm at the designated temperature.
In a typical mode, the preferred compositions herein that have an improved
tactile impression will comprise oleate:PEG weight ratios in the range
from about 1:2 to about 15:1, preferably from about 1:1 to about 10:1.
Tactile Impression--The compositions herein which contain the polyethylene
glycol are characterized not only by their excellent cleaning performance
and sudsing/rinsability properties, but also by their improved viscosity
properties and improved "feel". While, as disclosed above, the improved
viscosities of the compositions herein are readily demonstrated
quantitatively using standard measurement techniques, the improved feel of
the compositions which come into contact with the user's hands is a
qualitative tactile impression. However, this improved, "non-slippery",
"non-soapy" improvement in skin feel can be demonstrated by rubbing Test
(PEG-containing) and Control (no PEG) compositions on the hands or inner
forearms of volunteer graders. Even in such rudimentary tests, the graders
can readily distinguish the improved tactile impression of the
compositions made in accordance with this invention.
Optional Surfactants--Optionally, acid or base stable anionic surfactants
can be employed, as allowed by the United States Code of Federal
Regulations, Title 21, Section 173.315. Preferred are salts of
dodecylbenzene sulfonate, typically at levels up to 0.2%. Also described
in the CFR are phosphate esters of ethylene and/or ethylene/propylene
oxide adducts of aliphatic alcohols, dioctyl sulfosuccinate, or
2-ethylhexyl sulfate, typically but these materials surlier from lack of
stability at either acid or basic conditions.
Sequestrant/builder--The organic polycarboxylic acid, or salt thereof,
e.g., citric acid, is used as a sequestrant/builder in the acidic
compositions herein or sodium and/or potassium citrate as used in the
basic compositions herein are standard items of commerce. Other organic
poly carboxylic acids, especially those that are GRAS, such as tartaric,
malic, etc. acids, can also be used. When formulating the basic
formulations herein, it is preferred to use the potassium salt, as
compared with the sodium salt, to provide ease of formulatability. Complex
phosphates can also be used, but are generally avoided due to regulatory
considerations.
Buffer--Toxicologically-acceptable acidic or basic buffers can be used in
the compositions herein to maintain product pH in the acid or base range.
For ease of formulatability, it is highly preferred that such acidic and
basic buffers be in their potassium salt form. Citric acid is a preferred
acid pH buffer, and in the basic pH systems, potassium citrate is a
preferred dispersant for particulate soils. Potassium carbonate is a
convenient and preferred basic pH buffer. Sodium bicarbonate is a highly
desirable material to add to the compositions of this invention as a part
of the buffering system since it is readily available as baking soda in
food grade and is therefore relatively inexpensive, while providing a
highly desirable purity to the composition. Compositions formulated with a
mixture of potassium and sodium cations in molar ratios of from about 1:1
to about 10:1, preferably from about 2:1 to about 8:1, more preferably
from about 4:1 to about 5:1 potassium to sodium, e.g., as provided by
mixtures of potassium hydroxide (hydrate) and sodium bicarbonate, have
desirable rheological properties. The compositions are thick, so as to
cling to the fruit or vegetable until spread, but are readily dispensed,
e.g., by means of a spray device, either aerosol or finger-activated pump.
The levels and identities of the ingredients are adjusted to provide
products having the desired viscosities as set forth herein, e.g., more
than about 5, preferably more than about 10, more preferably more than
about 50 centipoise when at rest, and less than about 150, preferably less
than about 100, more preferably less than about 50 centipoise under shear
of .gtoreq..about.1000 sec.sup.-1.
The ability of the preferred compositions containing mixtures of both
sodium and potassium cations to shear thin is important to promote easy
dispensing, especially when the compositions are sprayed, while
maintaining the ability to be thick, cling, and delay run off after being
applied to the produce.
The pH is preferably not greater than about 12.5, and especially does not
contain large amounts of buffer at higher pHs for consumer safety,
especially when the compositions are sprayed.
Preservative--The strategy of formulating the present compositions at
either high or low pH is based on the reduced tendency for biological
growth of contaminants, such as bacteria, fungi, or molds, at either high
pH (>9) or low pH (<5). At neutral pH, an increased reliance on
preservatives is required to insure the lack of biological growth through
contamination in making or in use. The acidic compositions herein do
preferably contain a minimal amount, typically from about 0.01% to about
0.2% by weight, of a toxicologically-acceptable preservative in order to
prevent the growth of fungi, bacteria or like in the product on storage.
Standard food-grade preservatives such as potassium sorbate/sorbic acid
and/or sodium benzoate/benzoic acid, or mixtures thereof, are suitable for
such purposes. For example, from about 0.01% to about 0.2% of benzoic acid
or its sodium or potassium salts can be used. In general, the basic pH
compositions herein do not require a preservative, although one can be
added if desired.
Antioxidants The use of commercial oleic acid, or oleate salts, can be
complicated by development of off-odors and/or yellowing of the
compositions in which they appear. These undesirable properties are
believed to be caused by complex side reactions initiated by the reaction
of oxygen with primarily the polyunsaturated components of the fatty acid
stock. These results can be avoided, or minimized, by avoiding contact
with air, or by controlling the quality of the fatty acid stock so that
the amount and type of polyunsaturates are minimized as described above,
and/or by the addition of antioxidants.
It has been found, that the addition of tocopherols (e.g., Vitamin E, or
tocopherol acetates) in alkaline formulations is advantageous, as they do
not degrade, nor do they impart a strong color. They inhibit the
development of off-odors for extended periods of time so that the need for
masking scents is minimized, or eliminated, particularly for oleic acid
stocks of high quality, as described above. The use of butylated phenols,
such as BHT and BHA is also useful, but their effectiveness appears more
limited and they can impart stronger colors to the compositions. Other
food grade antioxidants such as Vitamin C and sulfites, are desirable to
prevent deterioration of the compositions by the action of oxygen, but
care must be taken since vitamin C can suffer color degradation and
sulfites can cause odor problems. Sulfites also have been the target of
potential health concerns. In acidic formulations, vitamin C can be
advantageous since its color degradation is less severe.
Fluid Carrier--The major proportion (typically, 90%-98%, by weight) of the
compositions herein comprises water as the solubilizing carrier for the
ingredients. As noted in the Examples hereinafter, water-ethanol can also
be employed and is especially preferred when formulating basic pH
compositions herein. The ethanol level preferably should not exceed 2% in
the solution used to clean the produce, to avoid an alcoholic odor,
especially when spraying. Other compatible, water-soluble, low molecular
weight solvents such as glycerol can also be used.
It has been discovered that for the acidic compositions (pH 5.5, and below)
described herein, a unique non-slippery solution feel is imparted by the
low pH compositions, especially at total levels of surfactant plus oleate
below about 3%. Such characteristic appears to be unique to these
compositions, compared to comparable compositions at neutral or high pH.
This solution feel is preferred for ease of handling and easy rinsing.
The compositions herein are preferably used by placing them in a package
comprising either an aerosol container or a non-aerosol spray device
"spray means." Said spray means is any of the manually activated,
preferably "trigger-type," means for producing a spray of liquid droplets
as is known in the art. Typical spray means are disclosed in U.S. Pat.
Nos.: 4,082,223, Nozawa, issued Apr. 4, 1978; 4,161,288, McKinney, issued
Jul. 17, 1979; 4,558,821, Tada et al., issued Dec. 17, 1985; 4,434,917,
Saito et al., issued Mar. 6, 1984; and 4,819,835, Tasaki, issued Apr. 11,
1989, all of said patents being incorporated herein by reference. The
spray bottle, or container can be any of the ones commonly used for
containing hard surface cleaner detergent compositions. Examples of
bottles are those in U.S. Pat. Nos. Des: 244,991, Weekman et al., issued
Jul. 12, 1977; and 275,078, Wassergord et al., issued Aug. 14, 1984, said
patents being incorporated herein by reference.
The spray means herein can also include those that incorporate a propellant
gas into the liquid and those that will foam even detergent compositions
having a viscosity of less than about 15 cps. The device can also be one
that can be adjusted to either give a liquid spray or a foam. The spray
means herein are typically those that act upon a discrete amount of the
composition itself, typically by means of a piston that displaces the
composition and expels the composition through a nozzle to create a spray
of thin liquid.
Preferred articles include the compositions herein that are suitable for
use in the processes described herein, in a package that can provide a
spray. Such articles are not widely marketed. This is surprising in view
of the clear advantages for such products for use by individual consumers.
The typical use involves treating individual items of produce, which would
make preparation of a "bath" wasteful.
In a preferred process for using the products described herein, and
especially those formulated to be used at full strength, the product is
sprayed onto the food product to be cleaned, rubbed, rinsed and/or wiped
off with a suitable material like cloth, sponge, a paper towel, etc.
Surprisingly, the compositions and processes described herein, especially
those that are alkaline, can provide effective disinfectancy.
All parts, percentages, and ratios herein are "by weight" unless otherwise
stated. All number values are approximate unless otherwise stated.
The following Examples illustrate the compositions and processes of this
invention, but are not intended to be limiting thereof. The exemplified
basic liquid compositions can be prepared at pH 9.5-12.3 by dissolving the
ingredients in water or water-ethanol using conventional mixing apparatus.
In a convenient mode, water is placed in a mixing vessel. Potassium
hydroxide, citric acid, the bicarbonate, glycerine (processing aid) and
ethanol are added in the named sequence, with stirring. The oleic acid is
added with high shear and stirring is continued. The PEG (which can
conveniently be predispersed in water) is then added. The optional perfume
ingredients can be added any time after the oleic acid has been dissolved
in the mixture.
EXAMPLE I
A concentrated acidic cleaning composition is prepared by dissolving the
following ingredients in water.
______________________________________
Ingredient % (wt.)
______________________________________
PLURAFAC RA-20 4.5
Oleic acid 0.25
Citric acid 2.0
Potassium citrate 2.0
Potassium sorbate 0.1
Sodium benzoate 0.1
Water Balance
______________________________________
Product pH 4
In use, for example, the composition of Example I is diluted 3-fold with
water and sprayed onto soiled fruits and vegetables such as apples,
grapes, peaches, potatoes, lettuce, tomatoes, celery, and the like, with
light scrubbing as may be required. After rinsing in tap water, the fruits
and vegetables are cleansed and ready for use.
EXAMPLE II
A concentrated basic cleaning composition is as follows.
______________________________________
Ingredient % (wt.)
______________________________________
Sodium oleate 3.0
Potassium citrate 1.5
Potassium carbonate
1.5
PLURAFAC RA-20 1.0
Ethanol 2.0
Water Balance
______________________________________
Product pH 11.5
The composition of Example II is prepared by adding oleic acid to ethanol
or ethanol/water, neutralizing with NaOH, and then dissolving the
resulting solution with the balance of the ingredients in water.
In use, for example, the composition of Example III is diluted 2-fold with
water and sprayed onto soiled produce, e.g., fruits and vegetables such as
apples, grapes, peaches, potatoes, lettuce, tomatoes, celery, and the
like, with light scrubbing as may be required. After rinsing in tap water,
the fruits and vegetables are cleansed and ready for use.
EXAMPLE III
Liquid compositions suitable for direct application to fruits and
vegetables, including by spray-on, are as follows:
______________________________________
% (wt.) % (wt.)
Ingredient Composition A
Composition B
______________________________________
Oleic Acid 2.64* 1.32
Ethanol 2.0 2.0
Glycerol 2.0 2.0
PEG (avg. mol. wt.)
0.5 (4600) 1.5 (8000)
KOH 1.49 1.23
KHCO.sub.3 0.65 0.65
Citric Acid 0.63 0.63
Oil Grapefruit Terpenes
0.04 0.02
EX-5-fold
Water Balance Balance
______________________________________
*Corresponds to 3% potassium oleate.
In-use, the compositions are applied through the commercial trigger-type
spray device used with the commercial product CINCH.RTM. directly to
soiled fruits and vegetables such as apples, grapes, peaches, potatoes,
lettuce, tomatoes, celery, and the like, with light scrubbing as may be
required. After rinsing in tap water, the fruits and vegetables are ready
for use. The waxy materials commonly used to reduce water loss for
extended storage life and to produce a sheen on apples can also be removed
by application of the compositions. An advantage of the consumer cleaning
produce is that materials serving a useful function, like wax on apples,
are removed immediately before use so as to prolong their effect as long
as possible.
If desired, the compositions of Example III can be concentrated up to about
5-fold by removal of a corresponding amount of water-ethanol solvent. The
concentrates are preferably diluted back to correspond to 3%-5% potassium
oleate prior to use in an immersion or spray-on cleaning operation.
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